Hi Folks,
I am trying to fully integrate GRASS database support into the PCI software
product, and I am somewhat confused about projections support. I am basing
my work on the GRASS 4.0 Programmer's Manual (DRAFT) dated August 11, 1992.
I am primarily utilizing the chapter on ``Database Structure'' which
defines the directory tree, and file formats within it.Recently I have discovered that some of our customers using GRASS have raster
layers with a ``proj'' code of 99 in the ``cellhd'' files, and projection
information in a file called PROJ_INFO in the PERMANENT directory. The
following is an example of one of these files:-------------------------------------------------------------------------------
Frank Warmerdam | Who can give them back their lives | warmerda@pci.on.ca
Software Artist | and all those wasted years? - Rush |
Frank,
The customers that have a 99 in the cellhd files are either SCS sites
or are co-operators that have received grass from SCS or are running
grass4.1. In grass4.0 SCS modified the projection information. CERL
did not change theirs until grass4.1. SCS has already converted to
grass4.1 for 85% of its operations.
The 99 is also in the WIND file which indicates you need to look in
the PROJ_INFO file for the true projection. This is where the
differences between SCS and CERL grass come into play. If you need
more details about SCS modifications for grass4.0 let me know.
Ken Sibley
USDA-SCS/NCG "Hell, if you understand everything I say,
ksibley@ncg.scs.ag.gov you'd be me!" - Miles Davis